The invention relates to an injection molding tool with at least one hot channel nozzle having a discharge opening which can be closed by a closure needle.
Such an injection molding tool is well-known in the state of the art and is almost routinely used in the manufacture of plastic parts. Since the discharge openings of the hot channel nozzle can be closed by a closure needle, plastic parts can be manufactured with a gate mark which is barely noticeable. That means that, with the known injection molding tools, plastic parts of very high quality can be manufactured.
It is however possible that the closure needle does not completely close the discharge opening. The reason may be for example a cooled plastic plug in the discharge opening. If, as a result, the discharge opening is not properly closed, this results in negative consequences to the gate mark of the plastic part. At the gate mark of the plastic part, there remains a feed head which may result in the plastic part to become a reject.
Since often such faults are not readily recognized, a multitude of unusable plastic parts may be produced. Obviously, this is very disadvantageous.
It is the object of the present invention to provide an injection molding tool of the type described above which is so designed that it can be determined whether the discharge opening of the hot channel nozzle is being closed by the closure needle.